Which wires go to my programmable thermostat?

[Jonno02]

Hi guys,

After some (hopefully simple) help here. I had a thread yesterday about a lazy Hive install by British Gas - which stem really helped me with yesterday.

According to customer services, the installation engineer is fairly defensive about his install, so just wanted to clarify the wiring before he comes back today.

The issue is with the upstairs programmable thermostat. This is on an S-plan system and is 'zone 1' (the red tape in the picture). This was controlled by a battery powered thermostat that had a brown and black wire going to it (see picture Thermostat). Rather than disconnect these and wire a receiver next to the wiring centre on the water tank, he's used these wires and installed a (battery powered) Hive thermostat with built in receiver as there was no live feed to power a receiver (which is no use to us as we need wireless). The Thermostat picture is actually the Hive thermostat.

I think I've traced the black wire at the thermostat to terminal 13. But I can't see where the brown wire is coming from. There are some discrepancies between what's there and the wiring shown on "Wiring diagram on tank" picture. So I just wanted to ask the professionals.

Really appreciate any help with clarifying this.

Cheers.

 

[stem]

All thermostats are is a simple on/off switch that require two wires. Modern thermostats with clever circuitry also require power of some sort to operate. For example, your existing thermostat uses battery power.

The Hive thermostat is also battery powered, it communicates wirelessly with a receiver which is mains powered. The diagram below shows the concept.

The "Two Thermostat Switching Wires" in your case are these.

They will now need to be connected to the Hive Single Channel Receiver. But as can bee seen in the above photo, there is not a 240V supply present at this point to power the receiver, so some rewiring is necessary. Either:

1. A new 240V supply from the heating system circuits can be run to the above location and the receiver installed where the present battery operated thermostat is, or the preferred method,

2. Install the receiver next to the wiring centre and connect it directly to the 240V supply and thermostat control wiring. Then the battery powered Nest thermostat can go where the existing thermostat is located. The original thermostat wires would then be redundant and could be removed.

 

[ianmcd]

he's used these wires and installed a (battery powered) Hive thermostat with built in receiver

There is no such Hive, your post is very confusing, that pic is not a hive thermostat

 

[Jonno02]

There is no such Hive, your post is very confusing, that pic is not a hive thermostat

Hi Ian. There is, according to the engineer and customer services, it's a newer model and apparently only available directly through British Gas.

2. Install the receiver next to the wiring centre and connect it directly to the 240V supply and thermostat control wiring. Then the battery powered Nest thermostat can go where the existing thermostat is located. The original thermostat wires would then be redundant and could be removed.

Hey stem, that's the preferred method. Customer service agent said that the engineer said he couldn't trace the wires at the wiring centre and so installed the wired thermostat.

 

[ianmcd]

Hi Ian. There is, according to the engineer and customer services, it's a newer model and apparently only available directly through British Gas.



Hey stem, that's the preferred method. Customer service agent said that the engineer said he couldn't trace the wires at the wiring centre and so installed the wired thermostat.

Post a pic of what you actually have , your post is talking about Hive and nest, nest do a battery receiver called Nest E, Hive thermostats are battery powered but the receivers require mains voltage

 

[Jonno02]

Post a pic of what you actually have , your post is talking about Hive and nest, nest do a battery receiver called Nest E, Hive thermostats are battery powered but the receivers require mains voltage

It's all Hive. What we were told is that now there's thermostats that utilise the existing wiring now rather than having a separate mains voltage receiver. Essentially just another programmable thermostat that connects to their app? The downside is that they are fixed to the wall and cannot be moved.

 

[stem]

I wasn't aware of a battery powered wired Hive thermostat that doesn't need a receiver. But if that's available you have been offered a good solution. The only advantage of using a wireless receiver is that you don't need to run wires out to the thermostat, but if they are already there the receiver version offers you no advantage. If it were me, I would definitely install the wired Hive thermostat that doesn't require a receiver in place of the existing thermostat.

I'm glad Hive have offered this solution at last, Tado have been doing it this way for years.

Moving a thermostat around is generally not a good idea anyway. A properly engineered heating system would have been designed around the selected optimum thermostat position. You will note for example that there will not be a TRV on the radiators in the room where the room thermostats are located.

 

[ianmcd]

That is a Hive wired thermostat, it is not a receiver, they are two completely different things hence the confusion in your post

 

[Jonno02]

I wasn't aware of a battery powered Hive thermostat that doesn't use a receiver. But if that's available you have been offered a good solution. The only advantage of using a wireless receiver is that you don't need to run wires out to the thermostat, but if they are already there the receiver offers you no advantage. I would definitely install the battery operated Hive thermostat that doesn't require a receiver.

Moving a thermostat around is generally not a good idea. A properly engineered heating system would have been designed around the selected optimum thermostat position. You will note for example that there will not be a TRV on the radiators in the room where the room thermostats are located.

There's a few problems with the wired one though:

1. The relay click is ridiculously loud. Like twice as loud as the click on the normal hive receiver. Not great in the middle of the night. Never quite heard a thermostat like it.
2. Even though it's a new build and the heating has been balanced umpteen times, it's trash. Boiler is woefully under powered for the size of house and will be changed out soon. Wireless thermostat was the point in getting Hive to be able to move it into the babies room once he moves out of ours, to ensure his room is kept at the correct temperature as his is at the end of the run.

That is a Hive wired thermostat, it is not a receiver, they are two completely different things hence the confusion in your post

Described exactly how it was explained by British Gas. Thanks for your input.

 

[stem]

Wireless thermostat was the point in getting Hive to be able to move it into the babies room once he moves out of ours, to ensure his room is kept at the correct temperature as his is at the end of the run.

In which case you will also need to remove the TRV from the babies room radiator (The TRV can interfere with the Hive and stop it working properly) and fit it to the radiator in your room which will now overheat without the room thermostat being there to control the temperature.

 

[Jonno02]

In which case you will also need to remove the TRV from the babies room radiator (The TRV can interfere with the Hive and stop it working properly) and fit it to the radiator in your room which will now overheat without the room thermostat.

Yeah we will do that. It's not an immediate issue as our room also doesn't heat up particularly well. The joys!

 

[ianmcd]

if you put the hive in the bedroom it will control all of the upstairs radiators and not just the one in the bedroom

 

[Jonno02]

if you put the hive in the bedroom it will control all of the upstairs radiators and not just the one in the bedroom

Yeah that's fine, as stem said we'll move the TRV. His room is the coldest so we don't want the heating clicking off with the current location of the stat and his room to still be cold. Which I appreciate stems from a fundamental issue with the heating system.